bioRxiv , 2023.2008.2025.554879
Even if a person gets enough vitamin B12 in their diet, some underlying health conditions can affect the absorption of vitamin B12 in the gut
Ringel et al., 2021), and IgM natural antibodies, TLR inhibitors, modulators of cellular components (neutrophils, basophils, eosinophils, mast cells, monocytes, macrophages, dendritic cells, regulatory T cells, natural killer cells) of innate immunity, cellular components of both innate and adaptive immune systems ( T cells, natural killer T cells), soluble constituents of adaptive immunity (polyreactive IgM antibodies to the viral disease, among others), and cellular components of adaptive immunity (T cell subsets like Th1 CD4+ T cells, cytotoxic CD8+ T cells, Th2 cells, Th17 cells, Th9 cells), viral replication inhibitors, renin-angiotensin system inhibitors (Williams, 2021) and human recombinant soluble ACE2 (Abd El-Aziz et al., 2020), as well as heparin and glycosaminoglycan antithrombotics (Magnani, 2021), among others
Think of it like this: if glutathione is the body's shield, a depleted level means the shield has cracks allowing harmful agents to wreak havoc